The use of fluxes such as fluorides, chlorides and carbonates in the alloy tablets in this industrial application presents some drawbacks related to the significant environmental problems they produce, and to the presence of inclusions in the obtained alloys. Thus, new fluxes of different characteristics are necessary in order to improve the features of the metals dissolution in relation to those given by the tablets currently used.
The published patents U.S. Pat. No. 4,880,462, U.S. Pat. No. 4,564,393 and UK-A-2.112.020 present an additive for this application, but the flux is of hazardous nature and makes undesirable inclusions in the aluminium can still be formed.
Patent GB-A-2.267.455 proposes the application of waxes in a different field: the powder metallurgy.